cyclic-gmp and Osteosarcoma

The prognosis of patients with osteosarcoma is poor; therefore, new treatment strategies are urgently needed. Phosphodiesterase 2 (PDE2) is one of the 11 families (PDE1-PDE11) of the phosphodiesterase superfamily that regulates the intracellular concentrations and effects of cAMP and cGMP. This in vitro study was performed to investigate the role of PDE2 in human oral osteosarcoma HOSM-1 cells.. PDE2 expression was measured by a cAMP-PDE assay and real-time-PCR. The effects of the PDE2-specific inhibitors, erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), 8-bromo-cAMP, and 8-bromo-cGMP on cell proliferation and migration were assessed.. PDE2 activity and PDE2A mRNA expression were detected in HOSM-1 cells. Cell proliferation was inhibited by EHNA and 8-bromo-cAMP but not by 8-bromo-cGMP. Cell migration was stimulated by EHNA and 8-bromo-cGMP, but it was inhibited by 8-bromo-cAMP.. Cell proliferation is regulated by PDE2-cAMP signaling and cell migration is regulated by PDE2-cGMP signaling in HOSM-1 cells.

Topics: Adenine; Apoptosis; Benzyl Compounds; Bone Neoplasms; Cell Cycle; Cell Movement; Cell Proliferation; Cyclic AMP; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 2; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Mouth Neoplasms; Osteosarcoma; Signal Transduction; Tumor Cells, Cultured

BACKGROUND The present work was performed to detect the potential inhibitory effect of cyclic guanosine monophosphate (cGMP)-dependent protein kinase II (PKG II) on epidermal growth factor (EGF) receptor-induced biological activity and related signal cascades in osteosarcoma cells. MATERIAL AND METHODS We transfected the osteosarcoma MG-63 cell line with an adenoviral vector encoding PKG II cDNA (Ad-PKGII) and incubated the transfected cells with 250 μM 8-pCPT-cGMP to activate the PKG II. We stimulated the MG-63 cells with100 ng/ml EGF, and then detected their proliferation using a CCK-8 assay. Transwell assay was used to examine MG-63 cell migration; and Western blot analysis was used to detect expression of matrix metalloproteinase 9 (MMP-9) and activation of ERK and Akt. RESULTS Stimulating cells by 100 ng/ml EGF promoted MG-63 cell proliferation and migration, ERK and Akt phosphorylation, and MMP-9 expression. These effects of EGF were inhibited in MG-63 cells infected with Ad-PKGII and incubated with 8-pCPT-cGMP. CONCLUSIONS Our results demonstrate that Ad-PKGII infection significantly inhibited EGF-induced proliferation and migration, as well as the associated-signal cascades; which indicates that PKG II might be a potential anti-cancer factor.

Topics: Bone Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type II; Epidermal Growth Factor; ErbB Receptors; Humans; Osteosarcoma; Phosphorylation; Protein Binding; Signal Transduction; Transfection

Human herpes simplex virus 1 (HSV-1) is a widespread pathogen, with 80% of the population being latently infected. To successfully evade the host, the virus has evolved strategies to counteract antiviral responses, including the gene-silencing and innate immunity machineries. The immediately early protein of the virus, infected cell protein 0 (ICP0), plays a central role in these processes. ICP0 blocks innate immunity, and one mechanism is by degrading hostile factors with its intrinsic E3 ligase activity. ICP0 also functions as a promiscuous transactivator, and it blocks repressor complexes to enable viral gene transcription. For these reasons, the growth of a ΔICP0 virus is impaired in most cells, except cells of the human osteosarcoma cell line U2OS, and it is only partially impaired in cells of the human osteosarcoma cell line Saos-2. We found that the two human osteosarcoma cell lines that supported the growth of the ΔICP0 virus failed to activate innate immune responses upon treatment with 2'3'-cyclic GAMP (2'3'-cGAMP), the natural agonist of STING (i.e., stimulator of interferon genes) or after infection with the ΔICP0 mutant virus. Innate immune responses were restored in these cells by transient expression of the STING protein but not after overexpression of interferon-inducible protein 16 (IFI16). Restoration of STING expression resulted in suppression of ΔICP0 virus gene expression and a decrease in viral yields. Overexpression of IFI16 also suppressed ΔICP0 virus gene expression, albeit to a lesser extent than STING. These data suggest that the susceptibility of U2OS and Saos-2 cells to the ΔICP0 HSV-1 is in part due to an impaired STING pathway.

Topics: Bone Neoplasms; Cell Line, Tumor; Cyclic GMP; Humans; Immediate-Early Proteins; Immunity, Innate; Membrane Proteins; Nuclear Proteins; Osteosarcoma; Phosphoproteins; Simplexvirus; Trans-Activators; Ubiquitin-Protein Ligases; Virus Replication

Natriuretic peptides and nitric oxide (NO) activate the cGMP/cGMP-dependent protein kinase (PKG) signaling pathway and play an important role in bone development and adult bone homeostasis. The cytokine IL-6 regulates bone turnover and osteoclast and osteoblast differentiation. We found that C-type natriuretic peptide and the NO donor Deta-NONOate induced IL-6 mRNA expression in primary human osteoblasts, an effect mimicked by the membrane-permeable cGMP analog 8-chlorophenylthio-cGMP (8-CPT-cGMP). Similar results were obtained in rat UMR106 osteosarcoma cells, where C-type natriuretic peptide and 8-CPT-cGMP stimulated transcription of the human IL-6 promoter and increased IL-6 secretion into the medium. Cotransfection of type I PKG enhanced the cGMP effect on the IL-6 promoter, whereas small interfering RNA-mediated silencing of PKG I expression prevented the cGMP effect on IL-6 mRNA expression. Step-wise deletion of the IL-6 promoter demonstrated a cAMP response element to be critical for transcriptional effects of cGMP, and experiments with dominant interfering proteins showed that cGMP activation of the promoter required cAMP response element binding-related proteins, and, to a lesser extent, proteins of the CAAT enhancer-binding protein and activator protein-1 (Fos/Jun) families. 8-CPT-cGMP induced nuclear translocation of type I PKG and increased cAMP response element binding-related protein phosphorylation on Ser(133). PKG regulation of the IL-6 promoter appeared to be of physiological significance, because inhibitors of the NO/cGMP/PKG signaling pathway largely prevented fluid shear stress-induced increases of IL-6 mRNA in UMR106 cells.

Topics: Animals; Bone Neoplasms; Cell Differentiation; Cell Line, Tumor; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Genes, Reporter; Humans; Interleukin-6; Nitric Oxide; Osteoblasts; Osteosarcoma; Promoter Regions, Genetic; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription, Genetic; Transfection

To study the effects of XW630 on bone formation in overiectomized (OVX) rats and in human osteoblast-like cell line TE85.. Bone histomorphometric analysis was performed with undecalcified bone sections and tetracycline intraperitoneally labeling.. Compared with that of OVX rats, the static data of trabecular bone volume (TBV)/total tissue volume (TTV), TBV/sponge bone volume (SBV) and mean trabecular plate density (MTPD) were enhanced while mean trabecular plate spacing (MTPS) decreased after treated with XW630 for 13w. The dynamic data of single-labeled surface [Sfract(s)], double-labeled surface [Sfract(d)], Sfract(d+1/2s), trabecular osteoid surface (TOS) and bone formation rate in tissue level (Svf) were increased and osteoid maturation period (OMP) shortened in XW630 group. In osteoblast-like cells, both 3H-thymidine incorporation and cell count increased after treated with XW630 for 48. Treated with XW630 for 12 approximately 18h, inducible nitric oxide synthase (iNOS) activity and cGMP content increased in time-dependent manners.. XW630 enhanced bone activation frequency and increased trabecular connectivity, stability, and strength. The cellular mechanism related to effects of XW630 on bone formation in ovariectomized rats.

Topics: Animals; Bone Neoplasms; Cell Division; Cyclic GMP; Estrone; Female; Femur; Humans; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Osteoblasts; Osteogenesis; Osteosarcoma; Ovariectomy; Piperazines; Rats; Rats, Wistar; Tetracycline; Tetracyclines; Tumor Cells, Cultured

To study the effects of 2-[3-estrone-N-ethyl-piperazine-methyl] tetracycline (XW630) in human osteoblast-like cell line TE85.. [3H]Thymidine incorporation and cell count for cell proliferation, radioimmunoassay for cyclic GMP (cGMP) content, and monitoring the conversion of [3H]arginine for inducible nitric-oxide synthase (iNOS) activity assay.. After treatment with XW630 for 48 h, [3H]thymidine incorporation and cell numbers increased by 62.7% and 96.9%, respectively. NG-monomethyl-L-arginine (L-NMMA, an NOS inhibitor) induced a concentration-dependent inhibitory effect on the proliferation after treatment for 48 h. The inhibitory effect was prevented partially by XW630 (1.0 nmol.L-1). After treatment with XW630 for 12-48 h, iNOS activity and cGMP concentration increased in time-dependent manners.. XW630 stimulated cell proliferation, enhanced iNOS activity and cGMP content in human osteoblast-like cell line TE85.

Topics: Bone Neoplasms; Cell Division; Cyclic GMP; Estrogens, Conjugated (USP); Estrone; Humans; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Osteoblasts; Osteosarcoma; Piperazines; Tetracycline; Tetracyclines; Tumor Cells, Cultured

Methyl, n-butyl 2'-TBDMS-N2-DMF-guanosine 3',5'-cyclic phosphate and 2'-TBDMS-N2-DMF-guanosine 3',5'-cyclic diethyl-phosphoramidate were synthesized by reaction of protected guanosine with trivalent phosphorus reagents in the presence of tetrazole followed by oxidation. The reaction occurred stereospecifically. Protected guanosine 3',5'-cyclic phosphotriesters and N, N'-diethyl-phosphoramidate were shown to have inhibitory activity on the synthesis of DNA and RNA in mouse liver tumor cell. Diastereoisomers of n-butyl N2-substituted guanosine 3',5'-cyclic phosphate have been shown to activate adenylate cyclase in vitro.

Topics: Adenylyl Cyclases; Animals; Cyclic GMP; DNA, Neoplasm; Liver Neoplasms; Mice; Osteosarcoma; Rats; RNA, Neoplasm

Topics: Adrenocorticotropic Hormone; Animals; Calcitonin; Cyclic AMP; Cyclic GMP; Glucagon; Glucose; Growth Hormone; Hormones; Insulin; Isoproterenol; Nucleotides, Cyclic; Osteosarcoma; Parathyroid Hormone; Prolactin; Prostaglandins; Rats; Theophylline; Thyroxine